[Zero10]

The coupler will bind on the shaft if it gets even a TINY bit crooked. Really, it's very picky.

I like to put a couple bolts back in the rack, pry the coupler upwards until it is about 1/4 of the way off, then take the bolts out, pulling the rack forward and prying the coupler upwards. Sometimes it helps to leave the passenger side bolts in a couple of turns to take some of the weight off during this step. If you think it's a PITA to get off, just wait until you are trying to get it back on.

Before re-assembly I use one of those battery terminal brushes and some WD-40 or an actual rust dissolver and scrub the heck out of the inside of the steering shaft coupler and the splined shaft on the rack. That extra couple thousandths of an inch really seems to help.